Alkoxylated nitrogen containing surfactants such as tallowamine ethoxylate and its quaternary surfactants find use as an adjuvant capable of enhancing pesticide activities. The most well-known application of tallowamine ethoxylate and its quaternary surfactants is to enhance glyphosate efficacy. In a typical tallowamine alkoxylate, the alkoxylation occurs on the nitrogen atom.
There has no prior art disclosing the use of a nitrogen containing surfactant with alkoxylation on the pendant (or secondary) hydroxyl group on the hydrocarbon chain.
Typically, in the alkoxylation of hydroxyl compound using an alkaline (OH−) as a catalyst, a polyalkylene oxide (PAO) chain is attached to the hydroxyl group. However, in the alkoxylation of triglycerides with pendant hydroxyl group, the great majority of the PAO chains are inserted to the ester group meanwhile only a minute portion of the PAO chains are attached to the hydroxyl group. The conventional alkoxylation reaction with an alkaline catalyst may be illustrated as shown in the following reaction (I):
where R1 and R2 each have 5-16 carbons, saturated or unsaturated, linear or branched alkyl groups; A is a C2-C3 alkylene; a, b, c, x, y and z each is equal or greater than 0; a+b+c+x+y+z=n. The reaction at the hydroxyl groups is minor, i.e., a+b+c>>x+y+z.
When a fatty acid (or ester) is used instead of the triglyceride, an ethoxylation reaction can be similarly illustrated as shown in the following reaction (II):

where R′ is H or methyl (or higher alkyl), R1, R2, x, and a are defined as in reaction (I) previously, and a>>x.
Non-limiting examples of fatty acids with a pendant hydroxyl group are castor acid and epoxidized soy acid.
Using ethoxylation of castor oil as an example, if the ethoxylation reaction of the castor oil is run using a Lewis acid, such as BF3 as catalyst, a surfactant is created in which the ethoxylation (EO) units were selectively attached to the OH groups on the fatty chain rather than inserted to the ester groups in the castor oil as it typically occurs with conventional alkaline catalyst process. That is, in reaction products in reactions (1), x, y and z each=0 to 7; a, b, or c is an integer of zero or more; x+y+z is more than about 95% of a+b+c+x+y+z. Similarly, in reaction products in reactions (II), x=0 to 7; a is an integer of zero or more; x is more than about 95% of a+x.
The selective ethoxylation attachment process can also be used for fatty acids, fatty acid esters, monoglycerides, and diglycerides. The selective attachment of PAO to the OH group can be confirmed by NMR analyses.
Using BF3 as catalyst, if more than ˜7 EO (per alkyl chain, i.e. x, y or z) is added, too much undesirable side product (dioxane) will be generated. However, if desired, more EO can be added subsequently by using KOH as catalyst without generating additional dioxane. When using KOH as catalyst, additional EO added will be both attached to the pendant ethoxylated groups and inserted to the ester groups. If one assumes equal reactivity, additional EO's will be equally distributed between attachment and insertion.
It should be noted that with regard to the PAO numbers in an alkoxylate, the PAO numbers of a, b, c, x, y, and z are average numbers. One skilled in the art understands that this is due to the nature of alkoxylation polymerization. For example, when x is 5, it means that the average PAO distribution is 5 PAO units on a particular hydrocarbon chain. Some molecules in the product may have zero PAO at the x position while some may have 12 PAO units at the x position.